Subsequent to the production of a large object it is common practice in quality assurance to inspect the object with a measuring system, such as a laser tracker system.
In a conventional laser-based measuring system, such as a laser tracker system, a probe target comprises measuring means, for example for tactile or optical measurements. Position determining means of the probe target are used by a laser-based measuring device, such as a laser tracker, to determine the position and attitude of the measuring target relative to the laser tracker and to determine the coordinates of a measurement point on an object being approached by the measuring means.
The functionality of a conventional laser tracker system is typically structured as follows:
The laser-based measuring system is designed to satisfy certain performance requirements, such as size, measurement accuracy and speed. The system dynamics is designed for allowing satisfaction of such requirements. A system controller is provided for running the system according to the required performance parameters, including system calibration for meeting an overall set of system specifications. Typically, a conventional laser tracker system is provided with a system software package comprising a basic software package and one or more additional feature software packages accomplishing the basic package.
A conventional process for measuring an object with a laser-based measuring system is structured as follows:
It is presupposed that CAD data of the object to be measured are available for preparation of the measurement. If this condition is satisfied, features of the object to be measured are selected. This regularly first implies choice of the way how the selected features shall be measured, and selection of a suitable measuring means. If there is a need for a datum then a way for realization of the datum is selected. Finally in the preparation phase, a part programme is selected, which may imply different degrees of automation, ranging from completely manual to fully automated generation of the part programme.
After accomplishment of the preparation phase, the execution phase of a conventional measurement process comprises the following steps:
Depending on required measurement accuracy and further required measurement and performance parameters, in the beginning a suitable laser-based measuring system is selected. Then typically the object to be measured is arranged at the laser-based measuring system, accompanied by the steps of calibrating the selected measuring means, setting up measuring system parameters, particularly also a targeted measurement accuracy and speed. The last steps of the execution phase comprise executing the measurement part programme and, finally, determining deviations between the CAD data and the measurement data of the real part.
The preparation of a laser-based measuring system for performing a measurement of an object takes a significant amount of time and efforts. Furthermore, precise measurements of features of objects of any kind require a variety of dedicated measurement tools or parts and availability of a large number of different measurement programmes.
DE 101 30 737 B4 discloses a system wherein a number of stations are used to measure and adjust cutting tools used on computer numerical control (CNC) machines. The units have measuring systems, controlled axes and are linked to local controllers that use local and remote software. The remote software is provided by a link over the internet to a central computer. The invention of DE 101 30 737 B4 is dedicated to solve the object of providing an adjustment device capable of performing a plurality of different measurement tasks in a flexible way and at low costs. For this purpose, according to DE 101 30 737 B4, a part of the system software is not resident on a local computer for device control, but on an external, central computer, thus reducing the requirements on the local control system. A user may be provided with remote software packages for measuring systems via the internet either for sale or for rent, or on any other basis, just only for the time when such “additional intelligence” is needed, this software being saved on and available from an external server.
Thus, system requirements to be realized on a user's site are reduced, but a support for improving the efficiency of working with the measuring system, particularly in the course of steps for preparation of a measurement, is not provided.